1. Field of the Invention
The invention relates to an electrical line for electrically conductively connecting two units arranged in a motor vehicle, wherein the line includes insulated electrical conductors which are surrounded by a common, electrically effective screen. Such a line is disclosed in EP 1 921 635 B1.
2. Description of the Related Art
Such a line can be used in a motor vehicle driven by an electric motor—in the following called “vehicle” for short—and also in a vehicle which has an internal combustion engine and an electric motor as drives in accordance with hybrid technology. The electric motor is in both types of embodiments of the drive fed from an appropriately dimensioned energy source. It is a three phase current motor in accordance with no technology by means of which an alternating current is produced by using an inverter which is also accommodated in the vehicle for the operation of the three phase current motor. For example, the energy source is an energy storage means which is composed of a plurality of capacitors (ultracaps) which may be accommodated in the trunk of a vehicle. The capacity of the capacitors is sufficient for a short term operation of the electric motor. They are recharged, for example, during braking operation of the vehicle by the electric motor which is then acting as a generator. For operating the electric motor, the electric motor is connected to the inverter by means of an electrical line, which in turn, is connected to the energy storage means through an electrical line. Consequently, “units” are in particular the electric motor, the inverter and the energy storage means.
EP 1 1921 635 B1 describes a cooling device for a vehicle which has a drive consisting of two motors, wherein the one motor is an internal combustion engine and the other is an electric motor connected through an electrical line to an inverter which is connected to the electrical energy source. The line consists of three electrical conductors which, together with at least two pipes in the form of a flat line, are arranged at a spacing from each other and are embedded in a common support of insulating material. The pipes are connected, on the one hand, to cooling elements of the energy source and the inverter and, on the other hand, are connected to a heat exchanger for forming a cooling agent cycle. A light wave conductor is arranged on one side of the support at a distance from one of the pipes connectable to the measuring and evaluating unit, wherein the measuring and evaluating unit serves to monitor the line for damage.
The cable according to U.S. 2005/0244116 A1 includes transmission elements which may also be electrical conductors which are arranged in a cable center around a tension proof core. The cable center is surrounded by several mechanically stable layers, wherein two steel reinforcements are among the mechanically stable layers. A synthetic casing is arranged over the outer steel reinforcement, wherein optical fibers are embedded in the outer steel reinforcement. These fibers are connected to a monitoring device. Damage to the cable is to be avoided by means of the fibers, which damage is produced for example, by heat, solvents, or other chemical substances. It is to be ensured in this manner that the transmission of sensitive data through the cable is not impaired.
The above mentioned EP 1 921 635 B1 discloses an electrical line which serves to electrically connect a unit mounted in a vehicle to an electric energy source which is also arranged in the vehicle and/or to another electrical unit. The line is constructed as a three phase line with three insulated electrical conductors, wherein each of the conductors has a circumferentially closed individual electrical screen which rests against its insulation. In addition, an outer screen is present which commonly encloses the three screened conductors with the intermediate arrangement of insulation material. At least at an end of the line, a coupling element equipped with electrical contacts which are insulated relative to each other or mounted in a moisture proof manner, wherein the electrical conductors, the individual screens thereof, and the outer screen are mounted separately of each other. Such a line is protected against electromagnetic radiation and it cannot produce any interference radiation as long as the screens are effective.